Push-in wire connectors typically include an insulative plastic housing with a modular metallic conductive clip disposed within the housing. Typically, the modular clip consists of at least two metallic pieces that are mechanically connected to one another. The plastic housing is used to insulate the electrical connection made between the conductive clip and the electrical conductors or wires. The modular conductive clip provides the functions of wire/conductor retention and electrical connection. Specifically, the one portion of the modular clip applies a force against the conductors or wires in order to retain them within the connector and more particularly within the clip once inserted into the housing. In addition, another portion of the modular clip provides an electrical connection between at least two conductors or wires when they are inserted into the connector and more particularly into engagement with the conductive clip.
As mentioned above, conventionally the conductive clip is a modular structure. Typically, the conventional clip consists of at least two separate structures which are mechanically connected to one another. Each of the structures performs only one of the retention or connection functions. For example, the conventional clip includes a spring member and a separate conductive plate or busbar. Typically, the spring and the conductive busbar are separate pieces which are assembled to provide a modular clip that performs the above-mentioned functions.
In addition, each portion of the conductive clip is typically constructed of different materials. For example, the spring member is usually constructed of a material that has good mechanical properties, such as stainless steel, to allow for flexure of the spring member. On the other hand, the busbar is constructed of a material which is a good electrical conductor, such as copper or tin-plated copper, to provide for electrical conductivity within the modular clip. When assembled, the spring member applies force against the wires inserted into the housing by clamping the wires against the busbar and the busbar portion of the clip acts as an electrical short to create an electrical connection between the wires inserted into the housing.
One of the challenges with the modular or two-piece conductive clip is that typically the clip must be pre-assembled before being positioned within the housing. The spring member and busbar are attached to one another by some mechanical means such as riveting, clamping or some other interlocking arrangement. Alternatively, an adhesive may also be used to connect the two pieces. However, regardless of the process, pre-assembly of a modular conductive clip before placement within the housing complicates the manufacturing process of the connector, in part, due to the necessary machinery and manpower required to assemble the modular clip. This additional pre-assembly results in higher manufacturing costs.
Other prior art push-in connectors have attempted to eliminate a step of the pre-assembly of the clip by designing connectors which do not require the spring and busbar to be physically connected to one another but instead are separately fixed with the housing. While this eliminates the pre-assembly of the clip itself, this clip still requires placement of two separate components within the housing. This again complicates the machinery needed to manufacture a connector which ultimately results in higher manufacturing costs.
There are connectors which incorporate a unitary or one-piece conductive clip. Such clips typically perform both functions of retaining the wires within the housing and creating an electrical connection between the wires. For example, such a clip is illustrated in U.S. Pat. No. 4,824,395. This clip includes a first flat base portion, a second upright portion with a plurality of openings aligned in a row, and a third spring portion which folds back toward the first portion to define a cantilevered spring. In use, the electrical wires first extend through the openings of the upright portion when the conductors are positioned within the housing. Once the electrical wires extend through the openings, they interact with the ends of the spring portions to be held in place. The spring portions provide a downward clamping force on the wires in order to retain them within the housing and prevent easy removal.
One of the challenges with such a one-piece conductive clip is that it only accommodates one row of connecting terminals located along the same plane. Although this design is useful when one desires a connector which is capable of connecting relatively few wires, (i.e., three or less), the connector becomes big and bulky when one desires a connector capable of connecting a greater number of wires. Oftentimes, electrical connectors are to be positioned within tight spaces and therefore spatial efficiency is important.
Other unitary or one-piece conductive clips provide busbars with separate landing or support areas for each conductor. For example, such a clip is illustrated in U.S. Pat. No. 6,893,286. The clip has a clamping leg which extends through a window in order to clamp a conductor on the support portions. One of the challenges with such clips is the conductivity issues that arise with the support portions that are each isolated from one another. Another challenge is the ease of accidental removal of a conductor from the clip. In clips that use the isolated supports, typically the clamping leg or spring finger clamps that conductor near the far edge of the isolated support of the bus bar. This configuration allows a user to tilt or otherwise orient the conductor in such a fashion that reduces the angle between the conductor and the spring finger and thereby allows the user to more easily remove a conductor.
Accordingly, there remains a need for a space efficient unitary or one-piece conductive clip which can be easily manufactured and efficiently assembled and is capable of making any number of reliable connections.